Our previous investigations (1976) of L-tyrosine catabolism revealed that certain species of Gram-positive bacteria utilize reactions that differ almost completely from those of the "classical" homogentisate pathway. Our proposed work for the future will be directed to elucidating the nature of intermediates and enzymes in a third pathway recently discovered by us in a yeast-like organisms from soil. We have already found that one intermediate, protocatechuate, is metabolized in an unusual fashion insofar as hydroxylation precedes ring-fission. Other benzenoid compounds for which the presence of three, rather than the usual two, hydroxyl groups are mandatory for ring-fission include phenylacetic acid and some of its homologs. These new hydroxylation systems will be investigated. In another area, we find that when methoxyl-substituted gentisic acids are degraded by certain bacterial species, methanol appears to be removed in one of the post-fission reactions by the action of an enzyme that expels methanol as it hydrates a double bond. Enzymes of this type will be purified and their mode of action investigated.